definately didn't lock it myself because I don't even know how to do that from the welcome screen. lol. You can lock it by using ctrl alt del if you don't use fast user switching, but if you DO use it, I'm not exactly sure how you lock a workstation. I have zone alarm installed now too. Hopefully this doesn't happen again, I have no idea what information they got off of here.. My documents folder is 80MB though.
if you had and credit card info or any other sensitive info in there i would get the card #'* changed and sutuff